Recording method for recording data on a recording medium

ABSTRACT

If a large minimum data unit for recorded data is used to record a small data amount of management information, the recording time is long, and furthermore when a WO (write once) is used as the recording medium, the number of recording operations which can be performed is restricted. 
     To solve the above problems, the present invention can record data in a management area in units smaller than ordinary units for recorded data to suitably record information in a limited management area and thereby efficiently use the user data area. At that time, the present invention simplifies interleave processing usually applied to ordinary recorded data, and performs the simplified interleave processing on a data structure (for data of small size) of the present invention so as to ensure the signal processing compatibility between the ordinary data and data having the data structure according to the present invention.

RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.10/117,212 filed on Apr. 8, 2002.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a recording/reproducing apparatus whichrecords data on a recording medium having a large capacity and has anarea for managing the data recorded on the recording medium. The presentinvention also relates to a recording/reproducing apparatus whichrecords data in units having different sizes, and arecording/reproducing method and a recording medium therefor.

2. Description of the Related Art

Recording/reproducing apparatuses for CDs (Compact Discs) and DVDs(Digital Versatile Discs) using optical disks as their recording mediaare widely used and are expected to increase in their recordingcapacity.

FIG. 5 shows a data structure used in the user data area in a DVD. Inthe figure, parities are added to user data in two different directions.Reference numeral 51 denotes the user data, specifically, one recordeddata block made up of 16 sectors, from sector 0 to sector 15. Referencenumeral 52 denotes the PI parity added in the row direction, whilereference numeral 53 denotes the PO parity added in the columndirection. Since the parities are added in the row and column directionsas shown in the figure, decreasing the number of the sectors (currently16 sectors) or decreasing the number of pieces of the user data to beemployed without changing the number of parities requires a significantchange in the recorded data block structure. Further, if the method foradding the parities is changed, it is necessary to carry out differentdecoding operations for the ordinary parity and the parity for thealtered data block structure in the reproduction, which complicates theconfiguration of the decode circuit and deteriorates the errorcorrection capability. Therefore, practically, the data must be recordedin minimum record block units of 32K bytes even when information to berecorded is small. Thus, a small data unit is difficult to record in thedata structure of the conventional DVD.

In the field of DVDs, recordable/reproduceable optical disks such asDVD-RAMs, on which data can be recorded a plurality of times, andDVD-Rs, on which data can be recorded only once, have been developedtogether with their recording/reproducing apparatuses.

In data recording on a disk, information for which data is recorded isrecorded in a specific management area and then read out to carry outthe control.

FIG. 6 shows areas on a DVD-R disk. The area consisting of a PCA (PowerCalibration Area) and an RMA (Recording Management Area) indicated byreference numerals 31 and 32, respectively, is an R-information area,which is the management area for the recorded data. Reference numeral 33denotes a read-in area, 34 denotes a user data recording area, and 35denotes a readout area, and 36 denotes the start of the next block ofrecorded information. Generally, the read-in area and the user data areaare separated such that their border exists between 02FFFFh and 030000hin terms of ECC block (correcting block) addresses. Further, the size ofthe RMA area is determined such that the RMA area can record apredetermined number of ECC blocks.

SUMMARY OF THE INVENTION

As shown in FIG. 6, the management area has a capacity of apredetermined number of blocks to record management information.

With this arrangement, if a large minimum data unit for recorded data isused to record a small data amount of management information, therecording time is long, and furthermore when a WO (write once) is usedas the recording medium, the number of recording operations which can beperformed is restricted depending on the size of the recorded data inthe management area. Since data is recorded in units of 32K bytes in aDVD, a 32K-byte area is allocated even to data whose size is less than32K bytes. Thus, a 32K-byte recording area is consumed each time data isrecorded. Therefore, when data is frequently recorded, unless there isstorage space left in the management information recording area, it isnot possible to record user data even if there is enough storage spaceleft in the user data area. This problem becomes more serious when theuser data area is increased by use of a technique providing higherdensity, etc.

The present invention has been devised in view of the above problem. Itis, therefore, an object of the present invention to suitably recordinformation in a limited management area so as to efficiently use theuser data area-when recording data.

The above problem can be alleviated by recording data in a managementarea in units smaller than ordinary units for recorded data.

Specifically, according to the present invention, a method for recordingdata on a recording medium comprises the steps of: combiningpredetermined n (n is an integer) number of pieces of data; adding errorcorrecting code to the data; adding addresses to the data; arranging thedata in a distributed manner; and, when management information isrecorded in a management area, combining and recording predetermined m(m is an integer and smaller than n) number of pieces of data.

When reproducing data, the present invention combines data in differentunits each corresponding to an area in the above recording medium fromwhich the (data) signals were reproduced.

Furthermore, when a plurality of record block sizes are used, thepresent invention records codes indicating the record block sizes ontothe recording medium. By detecting each code, it is possible to carryout reproduction processing corresponding to each record block size.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing a method for forming a record block from alarger record block and recording the formed record block according toan embodiment of the present invention;

FIG. 2 is a diagram showing a data structure of a data unit of data tobe recorded on a recording medium according to the embodiment;

FIG. 3 is a diagram showing a data arrangement in which each 2K bytes ofdata is put together into one logical block using the record block shownin FIG. 2;

FIG. 4 is a diagram showing a structure of data obtained as a result ofadding error correcting code to the 2K-byte logical blocks 1 to 4included in the record block shown in FIG. 3;

FIG. 5 is a diagram showing the data structure of user data in a DVD;

FIG. 6 is a diagram showing a configuration of areas on a DVD-R disk;

FIG. 7 is a diagram showing a 16K-byte recorded data structure formedfrom the 8K-byte recorded data structure shown in FIG. 1;

FIG. 8 is a diagram showing a 32K-byte recorded data structure formedfrom the 16K-byte recorded data structure shown in FIG. 7;

FIG. 9 is a diagram showing an example of how areas on a disk areactually assigned to data according to the embodiment of the presentinvention;

FIG. 10 is a diagram showing a configuration of a recording apparatusaccording to the present invention;

FIG. 11 is a diagram showing a configuration of a reproducing apparatusaccording to the present invention;

FIG. 12 is a diagram showing CPR_MAI in the data area in a DVD;

FIG. 13 is a diagram showing a data structure used to record data inunits of 4K bytes according to the present invention;

FIG. 14 is a sync and subcode arrangement used to record data in unitsof 4K bytes according to the present invention;

FIG. 15 is a diagram showing an example in which errors are included inportions of a sync and a subcode when a 4K-byte data structure accordingto the present invention is reproduced, indicating data positions atwhich the errors may be present;

FIG. 16 is another diagram indicating data positions at which errors maybe present when the 4K-byte data structure according to the presentinvention is reproduced; and

FIG. 17 is a diagram showing a method for processing data to be recordedaccording to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Symbols (reference numerals) mainly used in the figures indicate thefollowing: 101 denotes signal input; 102 addition of parity; 103addition of subcode; 104 interleave; 105 modulation; 106 a disk; 107system control; 109 a semiconductor circuit for processing recordingsignals; 110 output; 111 a process of putting data together inpredetermined units; 112 error correction; 113 address detection; 114deinterleave; 115 demodulation; and 119 a semiconductor circuit forprocessing reproducing signals.

A preferred embodiment of the present invention will be described belowwith reference to the accompanying drawings. FIGS. 2 and 3 show datastructures used to record user data according to the present invention.FIG. 1 shows an example in which the size of a record block is changedaccording to the present invention. FIG. 4 shows a data arrangementobtained as a result of rearranging the data structure shown in FIG. 3to actually record the data.

FIG. 2 shows a data structure of a record unit of data to be recorded ona recording medium according to the present invention. The followingdescription assumes that the recording medium is an optical disk.

The record block comprises: in each column, 496 bytes; and in each row,a sync (synchronization signal) of one byte, data of 38 bytes, and 3sets of a burst error detecting subcode of one byte and data of 38bytes; totaling 77,736 bytes. The arrow indicates the direction in whichdata is recorded on a disk. The LDC (Long Distance Code) portionsconstitute user data and are obtained as a result of adding 32 paritiesto 216 pieces of data, using an RS (Reed Solomon) code. In the figure,the code runs sequentially as a single column indicated by the shadedportion. However, the code may be divided and arranged by means ofinterleaving.

FIG. 3 shows a data arrangement in which each 2K bytes of data is puttogether into one logical block using the record block shown in FIG. 2.Thus, 32 2K-byte logical blocks can be arranged using the 64K-byterecord block. In addition to the above example, the logical blocks maybe arranged such that each 2 blocks are aligned in a row.

FIG. 4 shows the structure of data obtained as a result of adding errorcorrecting code to the 2K-byte logical blocks 1 to 4 shown in FIG. 3. Asshown in the figure, the error correcting code RS (248, 216, 31) isvertically (in the column direction) added to the data. Thus, the figureshows a case in which the error correcting code is added to thevertically aligned logical blocks 1 to 4. However, the error correctingcode may be added to the logical blocks 1, 16, 2, and 17 with the sameeffect. Thus, the present invention is not limited to a specificcombination of logical blocks; any combination may be employed by meansof regular interleaving.

FIG. 1 shows a method for forming and recording a record block smallerthan that shown above.

As shown in FIG. 2, the record block a comprises: in each column, 496bytes; and in each row, a sync of one byte, data of 38 bytes, and 3 setsof a burst error detecting subcode of one byte and data of 38 bytes;totaling 77, 736 bytes. The arrow indicates the direction in which thedata is recorded on a disk. The record block b1 comprises: in eachcolumn, 62 bytes; and in each row, a sync of one byte, data of 38 bytes,and 3 sets of a burst error detecting subcode of one byte and data of 38bytes, as in the case of the record block a; totaling 9, 672 bytes. Thedirection in which data is recorded on a disk is the same as that forthe record block a.

Data of 2048 bytes and an error check code of 4 bytes collectively forma recorded data unit, and the data of the record block a is made up of32 recorded data units. As for the record block b1, data of 2048*4 bytesand an error check code of 4*4 bytes collectively form its minimumrecorded data unit. The minimum recorded data unit is rearranged, asindicated by the record block b2 in the figure, to form a structure(arrangement) similar to that of the record block a which includes RScode (error correcting code), making it possible to use the same methodas that employed for the record block a for carrying out RAM control totemporarily store data for signal processing or performing errorcorrection processing. That is, error correcting code and then a subcodeare added to the structure of the record block b2. When recording thedata, the data is recorded as the record block b1 (using the structureof the record block b1). Since the subcode is a code string of 62 bytes,it may be added as a single column or arranged by means of interleaving.

Incidentally, data of 2048 bytes are roughly 2K bytes. Accordingly, therecord block b1 has a data structure for recording 8K bytes of datawhich includes 62 record block units each arranged in a row. However,the record block b1 is not limited to this specific data structure, thatis, this specific number of bytes, 8K bytes. The record block b1 (thatis, its data structure) may be of any size if it can be easily dividedand rearranged to form the data structure of the record block a.

On the other hand, a data structure made up of small blocks such asthose described above may make it impossible to interleave the data,deteriorating the error correction capability. To solve this problem,the same data may be recorded a plurality of times or error correctingparities may be added.

FIG. 7 shows a 16K-byte recorded data structure formed from the 8K-byterecorded data structure shown in FIG. 1. A 32K-byte recorded datastructure also can be easily obtained from the 16K-byte recorded datastructure using a similar method. FIG. 8 shows an area in the user dataarea of a DVD in which copy control information is recorded. In thefigure, the area CGMS (Copy Generation Management System) recordsinformation on user data, and therefore is not required as managementinformation data. Accordingly, management information may be recorded inthis area by coding the size of data to be recorded into a few types ofcode and recording the code. For example, when 2 bits are assigned tothe area CGMS, the flag “00” may be used to indicate an 8K byte recordeddata. The area for recording such information is not limited to the areaCGMS. Any area can be used to record such information if it is used foruser data and not included in the management area.

FIG. 8 shows a data structure larger than that shown above. As shown inFIG. 8, the record block d comprises 32K bytes of data, which is half ofthe 64K-byte record block a in size. Since DVDs record data in units of32K bytes, a record block of this data size can easily be madecompatible with a DVD system. With this record block, data to berecorded is added with parities and subcodes and then interleaved suchthat the data is distributed to enhance the burst error detectingcapability. The subcodes may be added after the interleave instead ofbefore the interleave. With the record block a, data is interleaved byadding parities to the data and then, for example, rearranging it. Withthis arrangement using an interleaving technique, when a burst error hasoccurred, two apparent burst errors half as long as the actual bursterror are detected. Therefore, even in the case where data cannot beserially reproduced due to the burst error, the data may be corrected byuse of the added parities if the apparent burst errors are within adistance of error correction by use of interleaving. To obtain such aneffect, the data is interleaved and then the subcodes added to theinterleaved data are also interleaved to enhance the error correctioncapability.

Since the record block d includes data smaller than that of the recordblock a, the same interleaving technique as that for the record block acannot be applied to the record block d. Accordingly, the subcodes areinterleaved within 248 bytes. By using such a method, it is possible toform and record a record block of 32K bytes. In each of the abovedescriptions, data is put together in units of a number of bytes closeto the nth power of 2 (n is an integer). This is not restrictive. Toround a fraction, redundant data may be added to produce a number easyto use when combining data.

FIG. 9 shows an example of how data to be recorded according to thepresent invention is actually recorded on a disk. The recording disk hasarranged thereon a management information area, a read-in area, a userdata area, and a readout area, and data is recorded in a predeterminedformat in each area. Data is recorded in predetermined record blockshaving 64K bytes in the user data area. As for the managementinformation area, data is recorded in record blocks having a block sizesmaller than 64K bytes, namely 4K bytes, 8K bytes, 16K bytes, or 32Kbytes. By recording data as described above, it is possible toefficiently record management information in a limited area. It shouldbe noted that even though the management area is provided inside theread-in area in FIG. 9, this relationship may be reversed.

Furthermore, if it is known beforehand that there is not enoughmanagement area, it may be arranged such that a definition can beestablished to extend it. For example, the border between the read-inarea and the user data area shown in FIG. 5 may not be fixed (eventhough it is fixed between 02FFFFh and 030000h in terms of ECC blockaddresses in the figure), and may be changed. In such a case, theposition of the changed border can be recorded in the first portion of aspecific area such as the management information area to extend themanagement area if it is known beforehand that a management area oflarge size is required.

FIG. 10 shows a configuration of a recording apparatus according to thepresent invention. Reference numeral 101 denotes a signal input sectionfor inputting data to be recorded; 102 an “addition of parity” sectionfor adding error correcting code; 103 an “addition of subcode” sectionfor adding information such as addresses in a distributed manner; 104 aninterleave section for rearranging data; 105 a modulation section forrecording data; and 106 a disk on which the data is recorded. Referencenumeral 107 denotes a system control circuit for controlling the system,while 109 denotes a semiconductor circuit for processing recordingsignals. Though not shown, a recording means is provided to record dataon a recording medium. The term “a recording means” here denotes, forexample, an optical head. A recording means may further include arecording optical system and a laser for recording. The term “acombining means” here indicates a means for putting together data to berecorded on a recording medium in predetermined units so that paritiescan be added to the data. For example, the process (section) 100 forcombining data into predetermined units shown in FIG. 10 is a combiningmeans. It should be noted that if there are a plurality of differentdata units (that is, each data unit consists of a different number ofbytes, etc.) in which data is put together, a different circuit may beused for each data unit, or alternatively a single circuit may be usedwhich is capable of changing the number (of bytes) constituting the dataunit. Further, an error correcting code adding means is a means foradding parities to data to be recorded on a recording medium. Forexample, the “addition of parity” section 102 shown in FIG. 10 is anerror correcting code adding means. An error correction code addingmeans may include a mechanism for storing data in a RAM, etc. andwriting/reading the data. It should be noted that if there are aplurality of different data units (that is, each data unit consists of adifferent number of bytes, etc.) in which data is put together, adifferent circuit may be used for each data unit as an error correctingcode adding means, or alternatively a single circuit may be used for alldifferent data units as an error correcting code adding means byswitching among different data units or among different data stringunits (each having a different number of bytes, etc.).

The system is controlled such that when data to be recorded ismanagement information and small, each piece of data entered from thesignal input section is set to be small and is not subjected to ordinaryinterleave processing but directly subjected to modulation and recordedon a disk by use of changeover switches after it is added with paritiesand subcodes. In the figure, the addition of subcode 103 is carried outbefore the interleave. However, it may be carried out after theinterleave, depending on the data to be recorded. Furthermore, even inthe above case in which data is not subjected to the ordinary interleaveprocessing by use of the changeover switches, the data may be subjectedto simple interleave processing which is suitable for small data to berecorded. The above processing operations may be switched by achangeover signal from the system control 107 or automatically switchedby means of address detection performed inside the semiconductor circuit109.

FIG. 11 shows a configuration of a reproducing circuit (apparatus). Areproduced signal from a disk 106 is demodulated by a demodulationsection (circuit) 115 and is subjected to address detection by anaddress detection section 113. Reference numeral 114 denotes adeinterleave section for rearranging data. The data is subjected toerror correction by an error correction section 112, and output from aterminal 111 after the data is put together in predetermined units.Reference numeral 119 denotes a semiconductor circuit for processingreproducing signals. The term “a demodulating means” here denotes ameans for demodulating data in a recording medium. For example, thedemodulation circuit 115 in FIG. 11 is a demodulating means. The term “areproduction combining means” here indicates a means for combining datareproduced from a recording medium in predetermined units correspondingto units in which the data was recorded, in order to carry out errorcorrection. This means corresponds to the process (address detectionsection) 113, shown in FIG. 11, for detecting the address of data andcombining the data in predetermined units. It should be noted that ifthere are a plurality of different data units (that is, each data unitconsists of a different number of bytes, etc.) in which data is puttogether, a different circuit may be used for each data unit, oralternatively a single circuit may be used which is capable of changingthe number (of bytes) constituting the error correction data unit basedon the address value. Further, an error correcting means is a means forcorrecting an error in data reproduced from a recording medium. Forexample, the error correction section 112 shown in FIG. 11 is an errorcorrecting means. An error correcting means may include a mechanism forstoring data in a RAM, etc. and writing/reading the data. It should benoted that if there are a plurality of different data units (that is,each data unit consists of a different number of bytes, etc.) in whichdata is put together, a different circuit may be used for each data unitas an error correcting means, or alternatively a single circuit may beused for all different data units as an error correcting means byswitching among different data units or among different data stringunits (each having a different number of bytes, etc.).

The system is controlled such that when data to be reproduced ismanagement information and small, the unit of data to be reproduced froma recording medium and error-corrected is set to be small and subjectedto error correction. When management information data of small size isread out, the location of the data is checked by means of addressdetection. By controlling changeover switches, the data is not subjectedto the ordinary interleave processing before it is, stored. Then, thedata is error-corrected in predetermined record blocks and output.

FIG. 12 shows the structure of CPR_MAI (Copyright ManagementInformation) in the data area in a DVD. Of the available 48 bits, only 4bits are currently used. Reference numeral b47 denotes CPM (CopyrightedMaterial) which indicates whether this sector includes a copyrightedmaterial; b46 denotes CP_SEC which indicates whether this sector has aspecific data structure for a copyright protection system; and b45 andb44 denote CGMS (Copy Generation Management System) which records copyrestriction information. Information on control of data copying must berecorded in the data area. However, copy information such as CGMS neednot be recorded in the management area. Accordingly, the followingarrangement can be made. The size of a record block in the managementarea may be coded into a code of 2 bits which is then recorded in theCGMS 2-bit area, making it possible to obtain the size of the recordblock.

FIG. 13 shows a data structure used to record data in units of 4K bytes.In the figure, reference numerals A to H each denote a data unit having19 bytes in each row and 31 bytes in each column. A record block e2comprises: two subcode strings each having 62 bytes including parities;and 19 code strings each having 248 bytes arranged in a column. Thesedata units (the record block e2) are rearranged into a record block e1having a data structure comprising 31 bytes in each column and 156 bytesin each row. By using such a data structure, it is possible to recorddata having a size of 4K bytes. Incidentally, if the subcode strings s1and s2 in the record block e2 are divided and rearranged as they are,the positions of the syncs after the rearrangement do not match thearrangement of the user data in the record block e1.

To solve this problem, as shown in FIG. 14, the syncs are inserted intospecific portions in the structure of the code strings s1 and s2, anddata, such as address information, and parities added to the data areput in the other portions. By using such a data structure of thesubcodes, it is possible to match the positions of the syncs with thearrangement of the user data.

FIG. 15 shows an example in which errors are included in portions of async and a subcode when the 4K-byte data structure illustrated in FIGS.13 and 14 is reproduced. In the figure, a sync N.G. and a subcode N.G.are indicated as error examples. Specifically, when a sync is notproperly detected or erroneous data is included in error correcting codefor subcode, the subsequent string must be processed since the stringmay be erroneous. When a sync detection N.G. or a subcode N.G. occurs,as described above, the error portions included in the data units A to Hcan be estimated from the position of the sync N.G. or the subcode N.G.as indicated by the shaded portions in the figure. By correcting errorsin data based on this information, it is possible to properly decode thedata. In such a case, the data may be recorded a plurality of times.

FIG. 16 shows another example (different from the example of FIG. 15) inwhich the case where a sync is not properly detected or erroneous datais included in error correcting code for subcode occurs a plurality oftimes serially, and the data between the errors is processed since thedata may be erroneous. Use of such an algorithm increases thereliability of information on the positions of errors in data, making itpossible to correct the data by discarding the erroneous portions.

FIG. 17 is a flowchart showing a method for processing the data to berecorded described so far, changing the structure of the data. First ofall, when data is recorded, it is determined whether the target area isthe management area at step 171, and if it is the user data area, thedata is processed in units of 64K bytes at step 172. Syncs and subcodesare added at step 173, and the data is interleaved to produce a recorddata structure at step 174. If the target area is determined to be themanagement area at step 171, on the other hand, the size of the data tobe recorded is determined at step 175. In this case, if the size of thedata to be recorded requires that the data be recorded in record unitsof 64K bytes, a 64K-byte record block is used (starting at step 176) torecord the data as in the case of the user data area. The sizes whichrequire that data be recorded in record units of 64K bytes include sizesa little smaller than 64K bytes (for example, 60K bytes or so) and sizeslarger than 64K bytes. Syncs and subcodes are added at step 177, and thedata is interleaved to produce a record data structure at step 178.

If the size of the data to be recorded is determined to be small at step175, an appropriate record block size is selected based on the size ofthe data to be recorded at step 179. As described above, a record blockcan be configured such that its size is set to be one of various sizessmaller than 64K bytes, such as 32K bytes (illustrated in FIG. 8), 16Kbytes (illustrated in FIG. 7), 8K bytes (illustrated in FIG. 1), and 4Kbytes (illustrated in FIG. 13). Accordingly, by selecting an appropriaterecord block size based on the size of data to be recorded, it ispossible to reduce an amount of data recorded in the management area.

Then, an identification code is added at step 180. The identificationcode indicates the size of a record block. The addition of syncs andsubcodes and the conversion of the data arrangement are carried outbased on the size of the record block indicated by this identificationcode. Specifically, at step 181, the data to be recorded and theidentification code are added with syncs and subcodes for small sizes.At step 182, the data is rearranged based on the size to produce data tobe recorded. By carrying out such processing, it is possible to recordeven data of small size in a disk management area.

According to the present invention described above, when data isrecorded on a recording medium, even data of small size to be recordedcan be subjected to recording signal processing in much the same way asordinary data (of ordinary size) to be recorded, making it possible torecord data in a management information area in small units.Accordingly, it is possible to reduce the time required for recordingmanagement information, and efficiently use the management informationarea.

1. A recording method for recording data on a recording medium having afirst area and a second area, said recording method comprising the stepsof: providing the recording medium; and recording data to be recorded inthe second area by a block unit of a second correction block, whereinsaid second correction block includes a synchronization signal, the datato be recorded in the second area, a subcode for detecting burst errorof the data to be recorded in the second area, said second correctionblock is smaller than a first correction block in the first area.
 2. Therecording method as claimed in claim 1, wherein said first area is adata area; and said second area is a management area.
 3. The recordingmethod as claimed in claim 1, wherein said second correction blockincludes the synchronization signal in its beginning column.
 4. Therecording method as claimed in claim 1, wherein said second correctionblock consists of 248 rows.
 5. The recording method as claimed in claim4, wherein data to be recorded in the second area is generated by adding32 correction codes to 216 data.